(i) Field of the Invention
The present invention relates to a facing material spray apparatus, and more particularly to a facing material spray apparatus for spraying a facing material on a mold surface which is to be used in carrying out facing as one of molding steps in sand mold casting.
(ii) Description of the Prior Art
Conventionally, there has widely been used a method for facing a mold surface with a substance (facing material) such as graphite, magnesia or zirconium before mold covering in order to perform sand-falling well and to make a casting surface smooth when carrying out molding in sand mold casting. More specifically, there is added to the facing material an iron oxide material or then like as and additive in an amount of about 10% by weight. Then, they are kneaded well and are coated on the mold surface by a brush or spray.
When using the brush or spray, however, a lot of time is required for coating so that it is hard to attain mass production. In addition, human labor is too great. Consequently, there has been used a facing material spray apparatus in carrying out facing.
The facing material spray apparatus mainly comprises a tank for housing a facing material, a facing pump attached to the tank for sucking the facing material in the tank, a nozzle attached to the pump for spraying the sucked facing material on a mold, a facing material receiver for receiving the facing material which is sprayed on the mold through the nozzle, and a recovery pump for recovering to the tank the facing material received by the facing material receiver.
According to the facing material spray apparatus of this type, the time for facing can greatly be shortened. In addition, the human labor can be reduced.
However, there are caused the following problems: (1) it is hard to regulate the concentration of the facing material and a lot of time is required to regulate the concentration, (2) piping portions are clogged with the facing material or molding sand, (3) it is difficult to completely carry out kneading so that the nonuniformity of facing can easily be caused. (4) the facing pump and recovery pump can easily break down, and (5) a lot of time is required to clean the tank, the pump and the like.
It is an object of the present invention to provide a facing material spray apparatus in which the above-mentioned drawbacks are eliminated.